package com.college.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.college.constant.ConfigConstant;

public class BuildImageServlet extends HttpServlet
{
	 /**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private Random generator = new Random();
	    private Color getRandColor(int fc, int bc) {
	        //给定范围获得随机颜色
	        Random random = new Random();
	        if (fc > 255) {
	            fc = 255;
	        }
	        if (bc > 255) {
	            bc = 255;
	        }
	        int r = fc + random.nextInt(bc - fc);
	        int g = fc + random.nextInt(bc - fc);
	        int b = fc + random.nextInt(bc - fc);
	        return new Color(r, g, b);
	    }

	    public BuildImageServlet() {
	    }

	    //private Font mFont=new Font("宋体", Font.PLAIN,12);//设置字体
	    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	        doGet(request, response);
	    }

	    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	        //设置页面不缓存
	        response.setHeader("Pragma", "No-cache");
	        response.setHeader("Cache-Control", "no-cache");
	        response.setDateHeader("Expires", 0);

	        // 在内存中创建图象
	        int width = 60, height = 20;
	        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

	        // 获取图形上下文
	        Graphics g = image.getGraphics();

	        //生成随机类
	        Random random = new Random();

	        // 设定背景色
	        g.setColor(getRandColor(200, 250));
	        g.fillRect(0, 0, width, height);

	        //设定字体
	        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));

	        //画边框
	        //g.setColor(new Color());
	        //g.drawRect(0,0,width-1,height-1);

	        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
	        g.setColor(getRandColor(160, 200));
	        for (int i = 0; i < 155; i++)
	        {
	            int x = random.nextInt(width);
	            int y = random.nextInt(height);
	            int xl = random.nextInt(12);
	            int yl = random.nextInt(12);
	            g.drawLine(x, y, x + xl, y + yl);
	        }

	        // 取随机产生的认证码(4位数字)
	        String sRand = "";
	        for (int i = 0; i < 4; i++)
	        {
	            String rand = String.valueOf(random.nextInt(10));
	            sRand += rand;
	            // 将认证码显示到图象中
	            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110))); //调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
	            g.drawString(rand, 13 * i + 6, 16);
	        }
	        // 将认证码存入SESSION
	        request.getSession().setAttribute(ConfigConstant.SYS_CAPTCHA, sRand);

	        // 图象生效
	        g.dispose();
	        // 输出图象到页面
	        try
	        {
	            ImageIO.write(image, "JPEG", response.getOutputStream());
	        }
	        catch (Exception ex)
	        {
	        }
 
	    }

	 
}
